Force http/1.1 for upgrade (Traefik v2)

build.Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.13-alpine
+FROM golang:1.14-alpine
 
 RUN apk --update upgrade \
     && apk --no-cache --no-progress add git mercurial bash gcc musl-dev curl tar ca-certificates tzdata \
@@ -19,7 +19,7 @@ RUN mkdir -p /usr/local/bin \
     && chmod +x /usr/local/bin/go-bindata
 
 # Download golangci-lint binary to bin folder in $GOPATH
-RUN curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b $GOPATH/bin v1.23.0
+RUN curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b $GOPATH/bin v1.23.8
 
 # Download golangci-lint and misspell binary to bin folder in $GOPATH
 RUN GO111MODULE=off go get github.com/client9/misspell/cmd/misspell

docs/content/contributing/building-testing.md

@@ -60,7 +60,7 @@ PRE_TARGET= make test-unit
 
 Requirements:
 
-- `go` v1.13+
+- `go` v1.14+
 - environment variable `GO111MODULE=on`
 - [go-bindata](https://github.com/containous/go-bindata) `GO111MODULE=off go get -u github.com/containous/go-bindata/...`
 

exp.Dockerfile

@@ -12,7 +12,7 @@ RUN npm install
 RUN npm run build
 
 # BUILD
-FROM golang:1.13-alpine as gobuild
+FROM golang:1.14-alpine as gobuild
 
 RUN apk --update upgrade \
     && apk --no-cache --no-progress add git mercurial bash gcc musl-dev curl tar ca-certificates tzdata \

go.mod

@@ -1,6 +1,6 @@
 module github.com/containous/traefik/v2
 
-go 1.13
+go 1.14
 
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 // indirect

pkg/server/service/roundtripper.go

@@ -23,12 +23,12 @@ func (t *h2cTransportWrapper) RoundTrip(req *http.Request) (*http.Response, erro
 	return t.Transport.RoundTrip(req)
 }
 
-// createHTTPTransport creates an http.Transport configured with the Transport configuration settings.
+// createRoundtripper creates an http.Roundtripper configured with the Transport configuration settings.
 // For the settings that can't be configured in Traefik it uses the default http.Transport settings.
 // An exception to this is the MaxIdleConns setting as we only provide the option MaxIdleConnsPerHost
 // in Traefik at this point in time. Setting this value to the default of 100 could lead to confusing
 // behavior and backwards compatibility issues.
-func createHTTPTransport(transportConfiguration *static.ServersTransport) (*http.Transport, error) {
+func createRoundtripper(transportConfiguration *static.ServersTransport) (http.RoundTripper, error) {
 	if transportConfiguration == nil {
 		return nil, errors.New("no transport configuration given")
 	}
@@ -66,25 +66,26 @@ func createHTTPTransport(transportConfiguration *static.ServersTransport) (*http
 		transport.IdleConnTimeout = time.Duration(transportConfiguration.ForwardingTimeouts.IdleConnTimeout)
 	}
 
-	if transportConfiguration.InsecureSkipVerify {
-		transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
-	}
-
-	if len(transportConfiguration.RootCAs) > 0 {
+	if transportConfiguration.InsecureSkipVerify || len(transportConfiguration.RootCAs) > 0 {
 		transport.TLSClientConfig = &tls.Config{
-			RootCAs: createRootCACertPool(transportConfiguration.RootCAs),
+			InsecureSkipVerify: transportConfiguration.InsecureSkipVerify,
+			RootCAs:            createRootCACertPool(transportConfiguration.RootCAs),
 		}
 	}
 
-	err := http2.ConfigureTransport(transport)
+	smartTransport, err := newSmartRoundTripper(transport)
 	if err != nil {
 		return nil, err
 	}
 
-	return transport, nil
+	return smartTransport, nil
 }
 
 func createRootCACertPool(rootCAs []traefiktls.FileOrContent) *x509.CertPool {
+	if len(rootCAs) == 0 {
+		return nil
+	}
+
 	roots := x509.NewCertPool()
 
 	for _, cert := range rootCAs {
@@ -100,7 +101,7 @@ func createRootCACertPool(rootCAs []traefiktls.FileOrContent) *x509.CertPool {
 }
 
 func setupDefaultRoundTripper(conf *static.ServersTransport) http.RoundTripper {
-	transport, err := createHTTPTransport(conf)
+	transport, err := createRoundtripper(conf)
 	if err != nil {
 		log.WithoutContext().Errorf("Could not configure HTTP Transport, fallbacking on default transport: %v", err)
 		return http.DefaultTransport

pkg/server/service/smart_roundtripper.go

@@ -0,0 +1,38 @@
+package service
+
+import (
+	"net/http"
+
+	"golang.org/x/net/http/httpguts"
+	"golang.org/x/net/http2"
+)
+
+func newSmartRoundTripper(transport *http.Transport) (http.RoundTripper, error) {
+	transportHTTP1 := transport.Clone()
+
+	err := http2.ConfigureTransport(transport)
+	if err != nil {
+		return nil, err
+	}
+
+	return &smartRoundTripper{
+		http2: transport,
+		http:  transportHTTP1,
+	}, nil
+}
+
+type smartRoundTripper struct {
+	http2 *http.Transport
+	http  *http.Transport
+}
+
+// smartRoundTripper implements RoundTrip while making sure that HTTP/2 is not used
+// with protocols that start with a Connection Upgrade, such as SPDY or Websocket.
+func (m *smartRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	// If we have a connection upgrade, we don't use HTTP/2
+	if httpguts.HeaderValuesContainsToken(req.Header["Connection"], "Upgrade") {
+		return m.http.RoundTrip(req)
+	}
+
+	return m.http2.RoundTrip(req)
+}